Execution of workflow applications on cloud middleware

Many scientific applications are often modeled as workflows. The data and computational resource requirements are high for such workflow applications. Cloud provides a better solution to this problem by offering a promising environment for workflow execution. Modeling as workflows involves tremendous data computations and resources thereby creating the necessity to coordinate the workflow process. Workflow Management System (WMS) serves this purpose by orchestrating the tasks of the workflow application by executing it on distributed resources. Pegasus is a renowned WMS that has been generally used in complex large scale e-applications. This paper gives an overview of the Pegasus WMS and provides the description of the environmental setup with open-stack middleware. The paper further includes details about the workflow creation and execution in Pegasus and discusses about the scheduling of workflows in cloud with its issues.